Changes in acidity, DOC, and water clarity of Adirondack lakes over a 30-year span

Abstract

Lake surveys conducted in 1987-88 and 2018-19 show changes in the chemical and optical properties of Adirondack lakes recovering from acidification. Among chronically acidified lakes (1980s pH < 5.5, ANC < 0 µeq L −1 ), increases in pH and reductions in monomeric Al were accompanied by significant increases in light attenuation, DOC, and CDOM. DOC-specific dissolved color (CDOM:DOC) doubled over the 30-year span, and is the likely factor accounting for loss of water clarity in Adirondack lakes during recovery from acidification. Monitoring data (1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002) from a subset of these lakes show that reductions in light attenuation were accompanied by stronger thermal stratification and greater hypolimnetic oxygen depletion. Lakes most affected by acidification experienced greater loss of water clarity during recovery relative to moderately acidified lakes. These findings are consistent with the hypothesis that lake acidification resulted in a reduction in light attenuation by CDOM resulting in greater water clarity in acidified lakes, and that this process has been reversed following regional declines in sulfate deposition.

The Roles of Tidal Marshes in the Estuarine Biochemical Processes: A Numerical Modeling Study

“…According to the limited DOC observations in the York River Estuary, the DOC concentrations range from 3 to 6 g m −3 , which agrees with our model results. However, large variations of DOC exchanges between the marshes and the adjacent water in the channels have been observed at different sites and times (Bukaveckas, 2021; Czapla et al., 2020; Neubauer & Anderson, 2003). These observations suggest that marshes may either be a source or a sink to DOC at different locations on the local scale.…”

“…In some areas, the tidal marshes tend to export excess materials, including organic carbon and other nutrients, into adjacent waters and thus enhance estuarine productivity in these systems (Alongi, 2020; Chicharo et al., 2008; Czapla et al., 2020; Odum et al., 1984; Ridd et al., 1988; Tzortziou et al., 2011). Differing results of the exported or filtered dissolved organic carbon are observed at different estuaries (Bukaveckas, 2021; Czapla et al., 2020; Neubauer & Anderson, 2003). The remineralization of the abundant organic matter, which can be directly exported from the marshes or from the increased local estuarine productivity, is suggested to cause excessive consumption of dissolved oxygen (DO) (Diaz & Rosenberg, 2001; Levin et al., 2009).…”

Phytoplankton Biomass Increases in a Silt-Impacted Area in an Amazonian Flood-Plain Lake Over 15 Years

“…Time series are essential tools to study longterm dynamics (Bukaveckas 2021). They detect trends and signals that may be overlooked in studies with a shorter time span (Dowd et al 2003) or processes with slow temporal dynamics.…”

How does lake water clarity affect lake thermal processes?

“…Water clarity is affected by substances within lake water, primarily aquatic plankton, suspended particles, and dissolved organic matter ( Aas et al., 2014 ; Shang et al., 2016 ). With the increasing availability of in situ observations and remote sensing data, researchers have carried out detailed studies on spatiotemporal distributions, changes, and the causes of lake water clarity at both single-lake and regional scales ( Wang S et al., 2020 ; Bukaveckas et al., 2021 ; He et al., 2022 ).…”